var reverseBits = function(n) {
    const M1 = 0x55555555; // 01010101010101010101010101010101
    const M2 = 0x33333333; // 00110011001100110011001100110011
    const M4 = 0x0f0f0f0f; // 00001111000011110000111100001111
    const M8 = 0x00ff00ff; // 00000000111111110000000011111111

    n = n >>> 1 & M1 | (n & M1) << 1;
    n = n >>> 2 & M2 | (n & M2) << 2;
    n = n >>> 4 & M4 | (n & M4) << 4;
    n = n >>> 8 & M8 | (n & M8) << 8;
    return (n >>> 16 | n << 16) >>> 0;
};

var reverseBits1 = function(n) {
    let res = 0
    for (let i = 0; i < 32; i++) {
        res = (res << 1) | (n & 1)
        n >>= 1
    }
    return res
};